From south-bay-birds-bounces+south-bay-birds-archive=[[email protected]] Sat Sep 27 20:09:59 2003 Received: from www.plaidworks.com (localhost [127.0.0.1]) by plaidworks.com (8.12.9/8.12.9) with ESMTP id h8S37TIB008358 for <[[email protected]]>; Sat, 27 Sep 2003 20:07:29 -0700 (PDT) Received: from sccrmhc11.comcast.net (sccrmhc11.comcast.net [204.127.202.55]) by plaidworks.com (8.12.9/8.12.9) with ESMTP id h8S36XZP008313 for <[[email protected]]>; Sat, 27 Sep 2003 20:06:34 -0700 (PDT) Received: from computer.comcast.net (12-234-255-153.client.attbi.com[12.234.255.153]) by comcast.net (sccrmhc11) with SMTP id <200309280306320110035hb6e>; Sun, 28 Sep 2003 03:06:33 +0000 Message-Id: <[[email protected]]> X-Sender: [[email protected]] (Unverified) X-Mailer: QUALCOMM Windows Eudora Version 5.2.1 Date: Sat, 27 Sep 2003 20:06:26 -0700 To: "Dr. Michael M. Rogers" <[[email protected]]>, [[email protected]] From: Alvaro Jaramillo <[[email protected]]> In-Reply-To: <[[email protected]]> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Cc: Subject: [SBB] Molt and that golden plover. X-BeenThere: [[email protected]] X-Mailman-Version: 2.1.2+ Precedence: list List-Id: South Bay Birding List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: south-bay-birds-bounces+south-bay-birds-archive=[[email protected]] Errors-To: south-bay-birds-bounces+south-bay-birds-archive=[[email protected]] At 03:44 PM 9/25/2003 -0700, Dr. Michael M. Rogers wrote: >I headed out the railroad tracks, hoping to refind the golden-plover >that Bob and Frank told me they had seen until shortly after 11:30am. >By the time I got out there it was not in the last pond, but once >again, by heading along the tracks towards the Marina I was able to >locate the molting adult GOLDEN-PLOVER SP. Initially it was pretty >close to the dike, but it flew further into the marsh almost >immediately. Also, it spent almost all of its time showing me its >left side (working its way north) so I never could assess the primary >projection on the right side. However, I did see the bird in flight >several times and that was instructive. It is indeed in primary molt, >with 2 or 3 inner primaries missing from both wings (symmetric molt). >As Al Jaramillo has noted, this molt timing is more consistent with >Pacific Golden-Plover rather than American. On the other hand, the >bird's feet did not noticeably protrude past the tail, something that >is usually apparent on the longer-legged Pacific Golden-Plover. The >good news is that this bird is likely to hang around for more viewing >given the condition of its wings. I think that the fact that there are two to three primaries being moulted on this bird is extremely significant. Personally, this seals the deal for me, I think it has to be a Pacific Golden Plover. There have been a couple of papers dealing with the difference in moult timing of first years and oversummering birds, but little on adults. Here is some info: Birds of the Western Palearctic - Vol.3 - fulva (Pacific) starts on breeding grounds from July with scattered feathers of face, underparts, and scapulars often shortly followed by P1 (primary1), especially in males and failed or non-breeders. Arrives in winter quarters, August, with 30-90% of face, forereneck, underparts, and cheeks, 10 - 50% of crown, mantle and scapulars, and occasionally some tail-coverts, tertials or tail feathers (mainly T2) in fresh non-breeding, moult of primaries (if started) suspended with inner 3-4 (2-5) primaries new. Moult continued September, primaries starting if not already begun on breeding grounds. ....... Nominate dominica (American GP) shows less moult on breeding grounds; wing, tail , and much of head and body replaced in winter quarters, September - February. Guide to the identification and ageiing of Holarctic waders (Prater, Marchant and Vuorien). This was the original shorebird ID bible first published in 1977. They mention that fulva (Pacific) starts wing moult in July-September; on the other hand dominica (American) shows no primary moult July - September, starting in October-December. Also look at the paper by Haverschmidt in the Wilson Bulletin, 1969 vol. 81(2):210-211; access this paper through the following site http://elibrary.unm.edu/wilson/ He notes the following " The first date of occurrence in Surinam is 1 September (1 September 1963 1 & 5 birds at Maasstroom (sight), 1 September 1966 Marienburg (specimen), 1 September 1967 Marienburg (sight) 1. All birds up to the middle of October were in full or in nearly full breeding plumage so it is apparent that adults arrive first." So in northern South America birds from September to October were still in really good full breeding plumage. Given that body moult begins before wing moult, and that wing moult does not occur during migration, especially in long-distance migrants we can surmise that primary moult in American Golden Plover should not kick in until October. Furthermore, active primary moult is extremely unlikely in migration stop-over spots, the Alviso plover is likely going to winter in California and it is behaving (in terms of primary moult) as if it was in the wintering grounds. All of this points to the bird being a Pacific Golden Plover. I know that thinking of moult timing as important in making identifications may seem odd, but much of this is very consistent in species that are not grossly out of range (such as those in the wrong hemisphere). cheers Alvaro Alvaro Jaramillo Biologist San Francisco Bay Bird Observatory P.O. Box 247 Alviso, CA 95002 (408)-946-6548 http://www.sfbbo.org/ [[email protected]] ***** NOTE NEW E-MAIL ADDRESS**** _______________________________________________ Do not post admin requests to the list. They will be ignored. south-bay-birds mailing list ([[email protected]]) Help/Unsubscribe/Update your Subscription: http://www.plaidworks.com/mailman/options/south-bay-birds/south-bay-birds-archive%40plaidworks.com This email sent to [[email protected]]